Mass Changes When A Reactant Or Product Is A Gas (GCSE Chemistry)

If 0.50 mol of gas is produced at room temperature and pressure, how many cm3 of gas is this (use 24 dm3 per mole)?

If a student collects 20.0 cm3 of gas at RTP in a measuring cylinder, how many moles of gas is this? (24 dm3 = 24 000 cm3 per mole)

When a metal reacts with oxygen in a sealed container (no matter leaves), what happens to the total mass of the sealed container and contents?

A reaction produces gas that is dissolved in the liquid rather than escaping. If later the liquid is heated and gas evolves, what will an open-balance measurement show while gas is dissolved and then after heating?

A carbonate reacts with acid producing 0.10 mol CO2 that escapes. What volume (in dm3) does this gas occupy at room temperature and pressure (24 dm3 per mole)?

24.0 cm3 of hydrogen is collected at room temperature and pressure in an open experiment where H2 escapes from the system. How many moles of H2 does this represent? (Use 24 dm3 = 24 000 cm3 per mole.)

A student collects gas from a reaction into an inverted measuring cylinder but fails to fill the trough with water high enough so some gas escapes. How will the experimentally measured mass change compare with the theoretical mass change?

When a reactant gas is used up in an open vessel and the gas is not replaced, which laboratory observation is expected?

Which experimental change will make the measured mass decrease during a reaction more accurately reflect the mass of gas evolved rather than being underestimated?

When magnesium ribbon burns in air to form magnesium oxide the measured mass of the sample increases. Why?

2H2 + O2 ? 2H2O. If 3.50 dm3 of H2 is reacted completely at room temperature and pressure, how much air (volume in dm3) is needed if air contains 20% oxygen by volume?